gh-10: add script to grow root fs

Uses growpart from cloud-utils and supports ext4 and xfs

base/etc/one-context.d/07-grow-rootfs

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+MOUNT_LINE=$(cat /etc/mtab | grep ' / ' | grep -v '^rootfs')
+
+DEVICE=$(echo "$MOUNT_LINE" | cut -d' ' -f1)
+FSTYPE=$(echo "$MOUNT_LINE" | cut -d' ' -f3)
+
+DISK=$(echo "$DEVICE" | sed 's/.$//')
+PARTITION=$(echo "$DEVICE" | sed "s|^$DISK||")
+
+if [ -n $DEBUG ]; then
+    echo DEVICE: $DEVICE
+    echo FSTYPE: $FSTYPE
+    echo DISK: $DISK
+    echo PARTITION: $PARTITION
+fi
+
+growpart "$DISK" "$PARTITION"
+
+case "$FSTYPE" in
+ext2|ext3|ext4)
+    resize2fs "$DEVICE"
+    ;;
+xfs)
+    xfs_growfs /
+    ;;
+esac
+